use the same mapping from opset to ir as in r1.5 branch

Author: guschmue

tests/test_optimizers.py

@@ -9,7 +9,7 @@
 
 import numpy as np
 from onnx import helper, TensorProto, OperatorSetIdProto
-from tf2onnx import utils
+from tf2onnx import utils, constants
 from tf2onnx.graph import GraphUtil
 from backend_test_base import Tf2OnnxBackendTestBase
 from common import unittest_main, group_nodes_by_type, check_opset_min_version, check_opset_max_version
@@ -69,8 +69,11 @@ def _make_onnx_const(np_val, output_name):
     def make_model(self, graph, producer_name="onnx-tests"):
         imp = OperatorSetIdProto()
         imp.version = self.config.opset
-
         model_proto = helper.make_model(graph, producer_name=producer_name, opset_imports=[imp])
+        try:
+            model_proto.ir_version = constants.OPSET_TO_IR_VERSION.get(self.config.opset, model_proto.ir_version)
+        except:  # pylint: disable=bare-except
+            pass
         return model_proto
 
     # Tranpose Optimizer Tests Start

tf2onnx/constants.py

@@ -39,7 +39,7 @@
 ENV_TF2ONNX_DEBUG_MODE = "TF2ONNX_DEBUG_MODE"
 
 # Mapping opset to IR version.
-# When adding here, make sure that the IR changes don't impact that we do.
+# Note: opset 7 and opset 8 came out with IR3 but we need IR4 because of PlaceholderWithDefault
 OPSET_TO_IR_VERSION = {
-    1: 3, 2: 3, 3: 3, 4: 4, 5: 3, 6: 3, 7: 3, 8: 4, 9: 4, 10: 5, 11: 6, 12: 7
+    1: 3, 2: 3, 3: 3, 4: 3, 5: 3, 6: 3, 7: 4, 8: 4, 9: 4, 10: 5, 11: 6, 12: 7
 }